: ·a-, L1Normal1No Spac Heading 1 Heading 2 Title Subtitle Paragraph Styles Key

Question

: ·a-, L1Normal1No Spac Heading 1 Heading 2 Title Subtitle Paragraph Styles Key Key Key Key Figure 10.1. The key lifecyce PLS NO PLAGIARISM 1. Guidance on key lengths changes over time. (a) Name two reputable sources for key length recommendations (other than the ECRYPT recommendations of Table 10.1) and explain why they are credible sources. (b) To what extent do their recommendations for symmetric key lengths match' the recommendations shown in Table 10.1? (c) Given a public-key cryptosystem, explain how experts might determine which key length for this algorithm is 'equivalent' to a symmetric key length of 128 bits.

Explanation / Answer

a.

Reputable sources for key length recommendation-

1.NIST Recommendations:

Came to use in 2016.NIST is a non-regulatory federal agency within U.S. commerce Department's Technology Administration.

It provides 19 types of key uses.Keys are authorized for use by legitimate entities in a specific cyptoperiod.

2.BSI Recommendation:

It is a German recommendation.It serves for Information Security in digitisation through prevention, detection and reaction for government, business and society.

b.

Key change is very important in system. If a same key is used for transacting there are chances that security might get compromised. Key change after every transaction allows system to make use of new keys which cannot be traced after a specific transaction.

New keys for every new usage seems to be more secure way.It limits the life of key to be cracked and hence adds to a level of security.

c.

Keys are used for operation of encryption and decryption. Various algorithms are used for this purpose. These algorithms need keys to be secure enough for transfer.

Relation between key length and security decided overall efficiency of a algorithm.Depending on the algorithm used it is usual to use different keys for same level of security.Keys are selected in such a way that it doesnt suffer from brute force attack.

Mostly experts tend to move to longer key sizes or more difficult algorithms to avoid brute force attacks at first.

Related Questions

Navigate

• Browse (All)
• Browse #
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.